GB2502833A

GB2502833A - Exhaust gas recirculation (EGR) cooling system

Info

Publication number: GB2502833A
Application number: GB1210219.0A
Authority: GB
Inventors: Carmine Pezzella; Luca Borgia
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2012-06-06
Filing date: 2012-06-06
Publication date: 2013-12-11
Anticipated expiration: 2032-06-06
Also published as: GB2502833B; GB201210219D0

Abstract

A cooling circuit 705 for an EGR system having an EGR valve (320,fig.1) and an EGR cooler 310, comprises an EGR cooler electric valve 760, an EGR cooler pump 770, an EGR cooler radiator 780 and an EGR water temperature sensor 795, such that the EGR cooling system is essentially a closed circuit being connected to a coolant system 700 of an internal combustion engine 110 by means of the electric valve 760, which allows the EGR cooling circuit 705 to be coupled to, or decoupled from, the engine coolant system 700. During early engine warm-up, the EGR cooler electric valve 760 and EGR cooler pump 770 are switched off. When the engine water temperature reaches a threshold temperature, eg 60oC, below which EGR cooling is inefficient eg because of condensation of HC on the heat exchanger surfaces, the valve 760 opens allowing coolant from the engine cooling system 700 to enter the EGR cooling circuit 705. When EGR coolant temperature is higher than the threshold temperature, the valve 760 is closed and the pump 770 is switched on, allowing EGR cooling to be controlled independently.

Description

METHOD FOR MANAGING A THRESHOLD TEMPERA TURE CONTROL IN AN

INTERNAL COMBUSTION ENGINE

TECHNICAL FIELD

The present disclosure relates to a method for managing a threshold temperature control for low temperature Exhaust Gas Recirculation (EGR) cooler in an internal combustion engine, particularly having a coolant system with a Switchable Water Pump (SWP).

BACKGROUND

It is known that, from the pollutants emission standpoint one of the internal combustion engine, particularly diesel engine, main problem are the NOx emissions. Due to the ever more stringent limitations, firstly an EGR system has been introduced and then it has been equipped with a cooler to improve the performance and reduce the impact on engine efficiency. The highest is the cooling efficiency the more are the advantages about both perspective. In general the cooling of recirculating exhaust gas is actuated using the water of the engine cooling system but the cooling capability is affected by the engine warm up. In some cases, the use of external circulation has been adopted for the EGR system, in order to let the EGR cooler water temperature be independent from the engine water temperature.

The technical problem of the existing EGR system provided with an EGR cooler is that there is a water threshold temperature under whom is not possible to actuate the cooling of gasses. If the water temperature is too low, the condensation of Hydrocarbons (HC) on the heat exchanger surfaces causes fouling effect. Consequently the heat exchange efficiency is drastically affected and clogging problems arises. Such temperature threshold depends on the EGR heat exchanger design but in general is around 60°C.

Therefore a need exists for a method that, having accurately estimated such temperature threshold, is able to provide an independent water management for the EGR cooling system, without increasing costs and complexity of the engine management system.

An object of an embodiment of the invention is to provide a dedicated cooling circuit for an EGR system provided with an EGR cooler. Such dedicated cooling circuit has a radiator, a dedicated pump and a temperature sensor. The EGR cooling system is connected to the main cooling circuit with an electric valve, that allows the coupling or the decoupling of the main engine coolant system with the EGR cooling circuit.

Another object of the invention is a method that combines the management of the engine coolant system with the low temperature EGR cooling, avoiding the usage of the EGR cooler below the critical water temperature. The method permits to: -check the engine water temperature, -trough the eletric valve, provide flow to the EGR cooling circuit, -close the electric valve to decouple the two circuits again -realize the cooling of EGR using the dedicate water pump and radiator.

Another object is to provide an apparatus which allows to perform the above method.

These objects are achieved by a cooling circuit, by a method, by an apparatus, by an engine, by a computer program and computer program product, and by an electromagnetic signal having the features recited in the independent claims.

The dependent claims delineate preferred and/or especially advantageous aspects.

SUMMARY

A first embodiment of the disclosures provides a cooling circuit for an EGR system provided with an EGR valve and an EGR cooler, comprising an EGR cooler electric valve, an EGR cooler pump, an EGR cooler radiator and at least an EGR water temperature sensor, wherein the EGR cooling system is essentially a closed circuit being connected to a coolant system of an internal combustion engine by means of said electric valve, which allows the coupling or the decoupling of the EGR cooling circuit with the engine coolant system.

An advantage of this embodiment is that it allows to have a separate cooling circuit for the EGR system, which according to the needs, can be coupled or decoupled to the internal combustion engine coolant system.

Infact, according to an aspect of the invention, said EGR cooler electric valve is closed and said EGR cooler pump is switched off, during the internal combustion engine warm-up phase.

An advantage of this aspect is that no low temperature water is circulated inside the EGR cooling circuit.

According to another aspect, said EGR cooler electric valve is open and said EGR cooler pump is switched off, if the engine water temperature is higher than an EGS threshold temperature Tts.

An advantage of this aspect is that engine water, having a temperature higher than a predetermined threshold, is circulated inside the EGR cooling circuit, thus avoiding HG condensation and cooling effect on the EGR cooler.

According to a further aspect, said EGR cooler electric valve is closed and said EGR cooler pump is switched on if the EGR water temperature is higher than the EGR threshold temperature Tts.

An advantage of this aspect is that the cooling water for the EGR system, having reached a temperature higher than a predetermined threshold, is circulated inside the EGR cooling circuit, independently on the engine coolant system.

According to a second embodiment, the invention provides a method for managing the cooling circuit of an EGR system in an internal combustion engine of an automotive system, the engine being provided with an EGR cooler, an engine coolant circuit, with at least a water pump and an engine water temperature sensor, the engine being also provided with an EGR cooling circuit according to the first embodiment, the method comprises: -decoupling the EGR cooling circuit from the engine cooling system, if the engine water temperature is below a threshold Tts, -controlling the temperature in the EGR cooling circuit, by a closed loop control of the EGR cooler pump.

Consequently, an apparatus is provided for performing the above method, the apparatus comprises: -means for decoupling the EGR cooling circuit from the engine cooling system, if the engine water temperature is below a threshold Its, -means for controlling the temperature in the EGR cooling circuit, by a closed loop control of the EGR cooler pump.

An advantage of this embodiment is to control the water temperature in the EGR cooling circuit, independently on the engine water temperature.

According to a first aspect of the invention1 after the internal combustion engine start, the method comprising: -determining if the engine water temperature is higher than the EGR threshold temperature and if yes, -opening the EGR cooler electric valve -storing the EGR water temperature, obtained by the EGR water temperature sensor, -determining if the EGR water temperature is higher than the EGR threshold temperature Tts and if yes, -closing EGR cooler electric valve and switching on the EGR cooler pump -determining if the EGR water temperature is higher than the EGR threshold temperature Its -if no, decreasing the flowrate of the EGR cooler pump, while if yes, increasing the flowrate of the EGR cooler pump.

Consequently the apparatus comprises: -means for determining if the engine water temperature is higher than the EGR threshold temperature and if yes, -means for opening the EGR cooler electric valve -means for storing the EGR water temperature, obtained by the EGR water temperature sensor, -. means for determining if the EGR water temperature is higher than the EGR threshold temperature Tts and if yes, -means for closing EGR cooler electric valve and switching on the EGR cooler pump -means for determining if the EGR water temperature is higher than the EGR threshold temperature Its -if no, means for decreasing the flowrate of the EGR cooler pump, while if yes, means for increasing the flowrate of the EGR cooler pump.

An advantage of this aspect is to avoid that the water temperature circulating inside the EGR cooling circuit is lower than a predetermined threshold, generally around 60°C. This measure avoids fouling formation at the EGR heat exchanger, reduces the risk of clogging and increases the life and the performance of the EGR cooler.

According to a second aspect of the invention, said water pump is a switchable water pump and the method, after the internal combustion engine start, and before the first step, further comprises the following steps: -switching on the switchable water pump, -storing the engine water temperature, obtained by the engine water temperature sensor, -switching off the switchable water pump, -storing the engine metal temperature, obtained by a metal temperature sensor or by an engine metal temperature map, -determining if the engine water temperature is higher than an engine threshold temperature Ti: if no go back to the previous step and if yes, 2 D -switching on the switchable water pump.

Consequently, the above apparatus for performing the method, further comprises: -means for switching on the switchable water pump, -means for storing the engine water temperature, obtained by the engine water temperature sensor, -means for switching off the switchable water pump, -means for storing the engine metal temperature, obtained by a metal temperature sensor or by an engine metal temperature map, -means for determining if the engine water temperature is higher than an engine threshold temperature Ti: if no go back to the previous means and if yes, -means for switching on the switchable water pump.

An advantage of this aspect is the possibility to apply the method to modem engines, provided with a switchable water pump.

According to another embodiment, the invention relates to an internal combustion engine of an automotive system, the engine being provided with an EGS, an EGR cooler, a coolant system, the coolant system comprising at least a water pump and at least an engine water temperature sensor, the engine being also provided with a cooling circuit for an EGR system according to the first embodiment, the automotive system comprising an electronic control unit, configured for carrying out the method according to the second embodiment.

An advantage of this embodiment is to avoid that the water temperature, circulating inside the EGR cooling circuit, is lower than a predetermined threshold, generally around 60°C.

According to another aspect, the internal combustion engine could further comprise a metal temperature sensor, said water pump is a switchable water pump and the electronic control unit is configured for carrying out the method according to the second aspect of the invention.

An advantage of this aspect is the possibility to apply the method to modern engines, provided with a switchable water pump.

The method according to one of its aspects can be carried out with the help of a computer program comprising a program-code for carrying out all the steps of the method described above, and in the form of computer program product comprising the computer program.

The computer program product can be embodied as a control apparatus for an internal combustion engine, comprising an Electronic Control Unit (ECU) a data carrier associated to the ECU, and the computer program stored in a data carrier, so that the control apparatus defines the embodiments described in the same way as the method. In this case, when the control apparatus executes the computer program all the steps of the method described above are carried out, The method according to a further aspect can be also embodied as an electromagnetic signal, said signal being modulated to carry a sequence of data bits which represents a computer program to carry out all steps of the method.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an automotive system.

Figure 2 is a section of an internal combustion engine belonging to the automotive system of figure 1.

Figure 3 is simplified scheme of the internal combustion engine, its coolant system and the EGR cooler cooling circuit.

Figure 4 is the scheme of figure 3 under an operating condition.

Figure 5 is the scheme of figure 4 under a further operating condition.

Figure 6 is a flowchart of a method for managing the cooling circuit for low temperature exhaust gas recirculation cooler, according to an aspect of the invention.

Figure 7 is a flowchart of the same method, according to another aspect of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Some embodiments may include an automotive system 100, as shown in Figures land 2, that includes an internal combustion engine (ICE) 110 having an engine block 120 defining at least one cylinder 125 having a piston 140 coupled to rotate a crankshaft 145.

A cylinder head 130 cooperates with the piston 140 to define a combustion chamber 150.

A fuel and air mixture (not shown) is disposed in the combustion chamber 150 and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston 140. The fuel is provided by at least one fuel injector 160 and the air through at least one intake port 210. The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 in fluid communication with a high pressure fuel pump 180 that increase the pressure of the fuel received a fuel source 190. Each of the cylinders 125 has at least two valves 215, actuated by a camshaft 135 rotating in time with the crankshaft 145. The valves 215 selectively allow air into the combustion chamber 150 from the port 210 and alternately allow exhaust gases to exit through a port 220. In some examples, a cam phaser 155 may selectively vary the timing between the camshaft 135 and the crankshaft 145.

The air may be distributed to the air intake port(s) 210 through an intake manifold 200.

An air intake duct 205 may provide air from the ambient environment to the intake manifold 200. In other embodiments, a throttle body 330 may be provided to regulate the flow of air into the manifold 200. In still other embodiments, a forced air system such as a turbocharger 230, having a compressor 240 rotationally coupled to a turbine 250, may be provided. Rotation of the compressor 240 increases the pressure and temperature of the air in the duct 205 and manifold 200. An intercooler 260 disposed in the duct 205 may reduce the temperature of the air. The turbine 250 rotates by receiving exhaust gases from an exhaust manifold 225 that directs exhaust gases from the exhaust ports 220 and through a series of vanes prior to expansion through the turbine 250. The exhaust gases exit the turbine 250 and are directed into an exhaust system 270. This example shows a variable geometry turbine (VGT) with a VGT actuator 290 arranged to move the vanes to alter the flow of the exhaust gases through the turbine 250. In other embodiments, the turbocharger 230 may be fixed geometry and/or include a waste gate.

The exhaust system 270 may include an exhaust pipe 275 having one or more exhaust aftertreatment devices 280. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some examples of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters. Other embodiments may include an exhaust gas recirculation (EGR) system 300 coupled between the exhaust manifold 225 and the intake manifold 200. The EGR system 300 may include an EGR cooler 310 to reduce the temperature of the exhaust gases in the EGR system 300. An EGR valve 320 regulates a flow of exhaust gases in the EGR system 300.

The automotive system 100 may further include an electronic control unit (ECU) 450 in communication with one or more sensors and/or devices associated with the ICE 110 and equipped with a data carrier 40. The ECU 450 may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE 110. The sensors include, but are not limited to, a mass airflow and temperature sensor 340, a manifold pressure and temperature sensor 350, a combustion pressure sensor 360, coolant and oil temperature and level sensors 380, a fuel rail pressure sensor 400, a cam position sensor 410, a crank position sensor 420, exhaust pressure and temperature sensors 430, an EGR temperature sensor 440, and an accelerator pedal position sensor 445. Furthermore, the ECU 450 may generate output signals to various control devices that are arranged to control the operation of the ICE 110, including, but not limited to, the fuel injectors 160, the throttle body 330, the EGR Valve 320, the VGT actuator 290, and the cam phaser 155. Note, dashed lines are used to indicate communication between the ECU 450 and the various sensors and devices, but some are omitted for clarity Turning now to the ECU 450, this apparatus may include a digital central processing unit (CPU) in communication with a memory system and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system, and send and receive signals to/from the interface bu& The memory system may include various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analog and/or digital signals to/from the various sensors and control devices.

The program may embody the methods disclosed herein, allowing the CPU to carryout out the steps of such methods and control the ICE 110.

Turning back to the internal combustion engine 110, in Fig. 3 a schematic engine coolant system 700 is represented. A water pump 710, preferably a switchable water pump 710, ensure the water circulation from the radiator 720 to the engine 110. The coolant system is also provided with a thermostat 730, preferably an electric thermostat 730, which opens the circuit from the radiator to the engine when the engine temperature reaches a certain threshold U, requiring the incoming of fresh water from the radiator. At least a water temperature sensor 790 and/or a metal temperature sensor are used for temperature monitoring. The engine is also provided with a cooling circuit 705 for the * EGR system 300. The EGR system comprises the EGR valve 320 and the EGR cooler 310, while said cooling circuit 705 comprises an EGR cooler electric valve 760, an EGR cooler pump 770, an EGR cooler radiator 780 and at least an EGR water temperature sensor 795. The EGR cooling circuit is connected to the internal combustion engine 110 coolant system 700 by means of said electric valve 760, which allows the coupling or the decoupling of the EGR cooling circuit with the engine coolant system, according to the needs of the EGR cooling.

As stated above, the problem to be solved by the invention is to avoid that the water, circulated inside the EGR cooling circuit, has a temperature lower than a threshold Tts, under whom is not possible to actuate the cooling of gasses. Infact, if the water temperature is too low, the condensation of Hydrocarbons (HC) on the heat exchanger surfaces would cause fouling effect. This would be the case during early engine warm-up phase and therefore in such conditions the EGR cooler electric valve 760 would be closed and the EGR cooler pump 770 switched off. Therefore, during early engine warm-up, no water circulation around the EGR cooler will take place.

As soon as the engine water temperature is higher than the threshold temperature Its, as shown in Fig. 4 the EGR cooler electric valve 760 opens, while the EGR cooler pump 770 is maintained switched off This allows water circulation coming from the engine coolant system 700 inside the EGR cooling circuit 705.

As soon as the water temperature inside the EGR cooling circuit 705 is higher than the threshold temperature Tts, as shown in Fig. 5, the EGR cooler electric valve 760 will be closed, while the EGR cooler pump 770 will be switched on. This allows an internal water circulation inside the EGR cooling circuit 705, where the temperature can be controlled in closed loop, by using an additional temperature sensor 795 on the EGR cooler return line and a PWM control on the EGR cooler pump 770. In this way, the water temperature control on the EGR cooling circuit is independent on the water temperature of the engine.

Therefore, the method for managing the EGR cooling circuit 705 starts (see Fig. 6) by storing 20 the engine water temperature, obtained by the engine water temperature sensor 790. Then1 an evaluation is performed determining 21 if the engine water temperature is higher than the EGR threshold temperature Tts. In case it is, the EGR cooler electric valve 760 is opened 22 (see also the scheme in Fig. 4). These first steps guarantee that no water is circulated inside the EGR cooling circuit, before the water overcomes a predetermined threshold. Then, according to the method, the EGR water temperature, obtained by the EGR water temperature sensor 795, are stored 23 and compared 24 with the predetermined EGR threshold temperature Tts. When the EGR water temperature is higher than the threshold, the EGR cooler electric valve 760 is closed 25 and the EGR cooler pump 770 is switched on. These further steps ensure that, once the EGR water temperature is higher than the threshold Tts, an independent water circulation is actuated inside the EGR cooling circuit (see also scheme in Fig. 5). Once the internal circulation, according to the scheme in Fig. 5, takes place, then the comparison 27 between the EGR water temperature and the EGR threshold temperature Tts goes on and the EGR water temperature is controlled by decreasing 28 the flowrate of the EGR cooler pump 770, if the EGR water temperature is lower than the threshold and by increasing 29 the flowrate of the EGR cooler pump 770, if the EGR water temperature is higher than the threshold. This simple strategy avoids that, in any engine operating condition, the water temperature in the EGR cooling circuit is lower than the predetermined threshold and consequently avoids fooling formation, thus increasing the efficiency of the EGR cooling. This strategy can be easily implemented in the current ECU 450, controlling the engine 110. 25.

If the internal combustion engine 110 is provided with a switchable water pump 710 and further comprises a metal temperature sensor 800 or alternatively an engine metal temperature map is provided by an experimental campaign, the above method (see Fig. 7), after the internal combustion engine start and before step 20, i.e: the check of the water temperature, comprises a sequence of steps using the possibility to switch on and switch off the pump to accelerate the engine warm up. In particular, with the pump 710 on 30, the engine water temperature, obtained by the engine water temperature sensor 790, is stored 31. Then, the switchable water pump 710 is switched off 32 and the engine metal temperature (either measured by means of the metal temperature sensor 800 or available by the engine metal temperature map) is stored 33. With the pump off, the engine warm up will be faster and the next step is to determine 34 if the engine water temperature is higher than an engine threshold temperature Ti. As soon as the water temperature will be higher than the threshold TI, the switchable water pump 710 will be let working again and the main procedure, as illustrated above with reference to Fig. 6, will start. In conclusion, we can state that the above method is fully applicable to modern internal combustion engines, provided with a switchable water pump.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

REFERENCE NUMBERS block

21 block 22 block 23 block 24 block block 26 block 27 block 28 block 29 block block 31 block 32 block 33 block 34 block block data carrier automotive system 110 internal combustion engine engine block cylinder cylinder head camshaft 140 piston crankshaft combustion chamber cam phaser fuel injector fuel rail fuel pump fuel source 200 intake manifold 205 air intake pipe 210 intake port 215 valves 220 port 225 exhaust manifold 230 turbocharger 240 compressor 245 turbocharger shaft 250 turbine 260 intercooler 270 exhaust system 275 exhaust pipe 280 aftertreatment devices 290 VGT actuator 23 300 exhaust gas recirculation system 310 EGR cooler 320 ECR valve 330 throttle body 340 mass airflow and temperature sensor 350 manifold pressure and temperature sensor 360 combustion pressure sensor 380 coolant temperature and level sensors 385 lubricating oil temperature and level sensor 390 metal temperature sensor 400 fuel rail pressure sensor 410 cam position sensor 420 crank position sensor 430 exhaust pressure and temperature sensors 440 EGR temperature sensor 445 accelerator position sensor 446 accelerator pedal 450 ECU 700 engine coolant system 705 EGR cooling circuit 710 water pump / switchable water pump 720 radiator 730 thermostat / electric thermostat 740 oil cooler 750 heater 760 EGR cooler electric valve 770 EGR cooler pump 780 EGR cooler radiator 790 Enginewater temperature sensor 795 EGR water temperature sensor 800 Metal temperature sensor Ti engine water temperature Tts EGR cooler threshold temperature

Claims

CLAIMS1. Cooling circuit (705) of an FOR system (300) provided with an EGR valve (320) and an EGR cooler (310)1 comprising an EGR cooler electric valve (760), an EGR cooler pump (770), an EGR cooler radiator (780) and at least an EGR water temperature sensor (795), wherein the FOR cooling system is essentially a closed circuit being connected to a coolant system (700) of an internal combustion engine (110) by means of said electric valve (760), which allows the coupling or the decoupling of the EGR cooling circuit with the engine coolant system.
2. Cooling circuit according to claim 1, wherein said EGR cooler electric valve (760) is closed and said EGR cooler pump (770) is switched off, during the internal combustion engine warm-up phase.
3. Cooling circuit according to claim 1 wherein said FOR cooler electric valve (760) is open and said FOR cooler pump (770) is switched off, if the engine water temperature is higher than an EGR threshold temperature (Tts).
4. Cooling circuit according to claim 1, wherein said EGR cooler electric valve (760) is closed and said EGR cooler pump (770) is switched on, if the EGR water temperature is higher than the EGR threshold temperature (Tts).
5. Method for managing the cooling circuit (705) of an EGR system (300) in an internal combustion engine (110) of an automotive system (100), the engine being provided with an EGR cooler (310), an engine coolant circuit (700), with at least a water pump (710) and an engine water temperature sensor (790), the engine being also provide with an EGR cooling circuit according to one of the previous claim, the method comprises: 18.-decoupling the EGR cooling circuit (705) from the engine cooling system (700) if the engine water temperature is below a threshold (Tts), -controlling the temperature in the EGR cooling circuit (705), by a closed loop control of the EGR cooler pump (700).
6. Method according to claim 5, wherein, after the internal combustion engine start, the method comprising: -determining (21) if the engine water temperature is higher than the EGR threshold temperature (Tts) and if yes, -opening (22) the EGR cooler electric valve (760) -storing (23) the EGR water temperature, obtained by the EGR water temperature sensor (795), -determining (24) if the EGR water temperature is higher than the EGR threshold temperature (Tts) and if yes1 -closing (25) EGR cooler electric valve (760) and switching on (26) the EGR cooler pump (770) -determining (27) if the EGR water temperature is higher than the EGR threshold temperature (Its) -if no, decreasing (28) the flowrate of the EGR cooler pump (770), while if yes, increasing (29) the flowrate of the EGR cooler pump (770).
7. Method according to claim 6, wherein said water pump is a switchable water pump (710) and the method, after the internal combustion engine start, and before step (20), further comprises the following steps: -switching on (30) the switchable water pump (710) -storing (31) the engine water temperature, obtained by the engine water temperature sensor (790), -switching off (32) the switchable water pump (710) -storing (33) the engine metal temperature, obtained by a metal temperature sensor (800) or an engine metal temperature map, -determining (34) if the engine water temperature is higher than an engine threshold temperature (11): if no go back to step (33) and if yes, -switching on (35) the switchable water pump (710)
8. Internal combustion engine (110) of an automotive system (100), the engine being provided with an EGR (320), an EGR cooler (310) a coolant system (700), the coolant circuit comprising at least a water pump (710) and at least an engine water temperature sensor (790), the engine being also provided with a cooling circuit (705) for an EGR system according to the claim 1, the automotive system comprising an electronic control unit (450), configured for carrying out the method according to claim 5 or 6.
9. Internal combustion engine (110) of an automotive system (100) according to claim 8, wherein the internal combustion engine (110) further comprises a metal temperature sensor (800), said water pump (710) is a switchable water pump and the electronic control unit (450) is configured for carrying out the method according to claim 7.
10. A computer program comprising a computer-code suitable for performing the method according to any of the claims 5-7.
11. Computer program product on which the computer program according to claim 10 is stored.
12. Control apparatus for an internal combustion engine, comprising an Electronic Control Unit (450), a data carrier (40) associated to the Electronic Control Unit (450) and a computer program according to claim 10 stored in the data carrier (40).
13. An electromagnetic signal modulated as a carrier for a sequence of data bitsIrepresenting the computer program according to claim 10.